Observing the Inverse melting of the vortex lattice in Bi$_2$Sr$_2$CaCu$_2$O$_8$ with point defects using Langevin simulations with vortex shaking

TL;DR

This study uses Langevin simulations to observe inverse melting of the vortex lattice in Bi$_2$Sr$_2$CaCu$_2$O$_8$, revealing a transition from ordered to amorphous vortex states consistent with experiments.

Contribution

First simulation to reproduce inverse vortex lattice melting in Bi$_2$Sr$_2$CaCu$_2$O$_8$ incorporating point defects and vortex shaking.

Findings

Observed inverse melting from Bragg-glass to vortex glass

Simulation results agree with recent experimental observations

Introduced a novel shaking and annealing process

Abstract

Langevin dynamics simulations of the vortex matter in the highly-anisotropic high-temperature superconductor Bi$_2$Sr$_2$CaCu$_2$O$_8$ were performed. We introduced point defects as a smoothened distribution of a random potential. Both the electromagnetic and Josephson interactions among pancake vortices were included. A special shaking and annealing process was introduced to let the system approach the equilibrium configuration. We are able to see the inverse melting transition from the Bragg-glass to the amorphous vortex glass state, in agreement with recent experiments.